The present invention relates to a dual cargo vehicle, that is, a vehicle which selectively may be converted for the shipment and discharge of different types of material, and particularly to a ship or similar vessel which may selectively be converted for the transport and discharge of pulverulent materials, such as cement, and material in lump form such as coal or ore. The present invention is particularly related to such dual cargo vessels which are provided with hoppers having bottom discharge outlets.
One such dual cargo vessel is disclosed in U.S. Pat. No. 3,191,998, issued to Charles L. Howlett on June 29, 1965. That patent discloses an unloading system which includes two unloading conveyors in the bottom of the vessel, viz., a screw-type conveyor for unloading pulverulent material and a belt-type conveyor for unloading lump material, the two conveyors being arranged in side-by-side relationship. The system also includes two different and independently mounted discharge gates for discharging different types of material from the hopper outlets. For discharging lump-type material to the belt conveyor, a tilt gate is mounted on a carriage for movement between open and closed positions with respect to the associated hopper outlet. When it is desired to discharge pulverulent material to the screw conveyor, the tilt gate is moved by pneumatic means entirely out of the way to accommodate movement of an airslide and chute unloading arrangement into position beneath the hopper outlet.
Thus, in that prior art system the two different discharge assemblies are completely independent of each other. Two separate and independent mounting and drive assemblies are provided respectively for the two discharge assemblies, and they are adapted for discharge respectively into two separate and independent unloading conveyors. This duplication results in an extremely complex and expensive system which occupies a considerable amount of space in the vessel.